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NCBS: Weight Loss and Weight Regain Expected After Procedure (2009)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

The purpose of the study was to evaluate independent prognostic factors by multivariate analysis of treatment outcome after laparoscopically placed adjustable gastric banding (LGB) implantation.

Inclusion Criteria:
  • BMI greater than 41kg per m2
  • BMI greater than 35kg per m2 and obesity-associated diseases
  • Age between 18 and 65 years
  • Minimal period of five years overweight
  • At least one unsuccessful conservative treatment for greater than one year
  • No endocrinologic disease
  • No psychiatric disorders
  • No abuse of alcohol and drugs
  • No general contraindications for surgery.

 

Exclusion Criteria:
  • Hormonal diseases
  • Psychiatric diseases
  • Alcohol abuse
  • Drug abuse.
Description of Study Protocol:
  • Recruitment: 99 consecutive bariatric surgery patients
  • Design: Prospective cohort study
  • Blinding used:Not applicable
  • Intervention:Laparoscopic banded gastroplasty
  • Statistical Analysis:
    • The multivariate analysis was used for the onset of obesity, feeling of post-prandial satiety after LGB and initial BMI
    • A logistic regression analysis model was used for excess body weight reduction greater than 25% after LGB after one and two years post-surgery.
Data Collection Summary:
  • Timing of measurements: Three, six, nine, 12 and 18 months; after the second year, re-evaluation was performed annually through 72 months
  • Dependent variables: Weight loss and satiety
  • Independent variables: LGB
  • Control variables:
    • Post-operative oral feeding
    • Psychosomatic therapy prior to surgery
    • Intensive program to change food and eating behavior.
Description of Actual Data Sample:
  • Initial N: 99 patients (83 females, 16 males)
  • Attrition (final N): 89 patients
  • Mean age: 37 years (range 20 to 67 years)
  • Ethnicity: Not mentioned
  • Other relevant demographics: Not Applicable
  • Anthropometrics: Pre-surgical mean BMI 49.3kg per m2 (range 32.4 to 72.6kg per m2) 
  • Location: Albert-Ludwig University of Freiburg, Germany.
Summary of Results:
  • Overall, the subjects reduced excess body weight by 28% during 72 months of follow-up
  • The authors performed multivariate analyses on patients who had excess body weight reduction of greater than 25% after LGB
    • 57 experienced good post-prandial satiety, lost more of excess weight in first year and maintained weight loss (P<0.001)
    • 21 patients experienced poor post-prandial satiety and regained weight.
  • Patients with initial BMI of 45 or more had best probability of achieving greater than 25% loss of excess body weight
  • Age of onset of obesity was not a significant predictor of success of weight loss after surgery.
Author Conclusion:

Patients' ability to change eating behavior depends on feeling of satiety after meals. Thus, patients should be followed for several years after surgery so band can be adjusted as needed.

 

 

 

Funding Source:
University/Hospital: University of Frieburg
Reviewer Comments:
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? Yes
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? No
  4.4. Were reasons for withdrawals similar across groups? ???
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? No
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? No
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) No
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? No
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? No
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? No
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? No
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.6. Was clinical significance as well as statistical significance reported? No
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? N/A
  10.2. Was the study free from apparent conflict of interest? Yes